Objective:To investigate the effect of 3, 3′-diindolylmethane(DIM)on paclitaxel-resistant non-small cell lung cancer A549/T cells and explore its underlying mechanism.Methods:Western blotting was used to detect transferrin receptor(TFRC), solute carrier family 7 member 11(SLC7A11), and glutathione peroxidase 4(GPX4)in human normal bronchial epithelial BEAS-2b cells, human NSCLC A549 cells, paclitaxel-resistant human NSCLC A549/T cells, and human large cell lung cancer H460 cells to select the optimal cell line. A549 and A549/T cells were treated with various concentrations of DIM(0, 20, 40, 80, 160 μmol/L), and cell proliferation was assessed by CCK-8 assay; and the expression of TFRC, SLC7A11 and GPX4 proteins in A549/T cells were determined by Western blotting to screen out the optimal DIM concentration. Additionally, A549/T cells were divided into the control group, which was cultured in high-glucose medium containing 10% fetal bovine serum for 24 h; the Erastin group, treated with 10 μmol/L Erastin for 12 h alone; the DIM group, treated only with 80 μmol/L DIM for 24 h; the DIM+Erastin group, cells were pre-treated with 10 μmol/L Erastin for 12 h, then treated with 80 μmol/L DIM in the following 24 h. Cell viability was detected by CCK-8 assay, and the expression of TFRC, SLC7A11 and GPX4 proteins was assessed by Western blotting.Results:Compared with the BEAS-2b group, TFRC and SLC7A11 expression was significantly increased in A549 cells(P<0.05), TFRC, SLC7A11 and GPX4 expression was significantly increased in A549/T cells(P<0.05). No significant differences in TFRC, SLC7A11 and GPX4 expression were observed in H460 cells(P>0.05). In A549/T cells, compared with the 0 μmol/L group, the expression of TFRC, SLC7A11 and GPX4 proteins showed significant alterations in the 80 μmol/L DIM group(all P<0.05). Compared with 0 μmol/L DIM group, in A549 cells, cell viability was significantly decreased in 20, 40, 80 and 160 μmol/L DIM groups(all P<0.05);in A549/T cells, cell proliferation was significantly decreased in 80 and 160 μmol/L DIM groups(all P<0.05). In A549/T cells, compared with the control group, DIM group, Erastin group and DIM+Erastin group showed a significant increase in TFRC expression(all P<0.05), while the expression of SLC7A11 and GPX4 proteins significantly decreased(all P<0.05), and cell proliferation significantly decreased(all P<0.05).Conclusion:DIM may inhibit the proliferation of paclitaxel-resistant non-small cell lung cancer A549/T cells by inducing ferroptosis, and ferroptosis inducers could be used to enhance the anti-cancer effect of DIM.